<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>

  <script type="text/javascript">
        var user = {
        name : "秦家",
        age : 3,
        sex : "男"
        };
//js->json
        var json = JSON.stringfy(user);
        console.log(json);
//json->obj
        var obj = JSON.stringfy(json);
        console.log(obj);
  </script>

</head>
<body>
</body>
</html>